Production of chloropropionic esters



Patented at. 29, 1932 TED TATES PATENT OFFICE we rrrnsrrscnnn am: n-Hmn JACOBI, GI LUDWIGSHAFEN-ON-THE-BHINE,

FRANWQBT-QN-TEE-MAIN, GEBMAHY PEQDUGTIQN 9E @HLOEQERQPIGNIC ESTEEfi Ho Drawing. Appllcatieedled Hay-9,

The present invention relates to the production of ,chloropropionic esters.

The methods of preparing ,B-chloropropicnic acid already known are alike expensive and inconvenient. Thus for example the direct chlorination of propionic acid leads to a mixture of chlorinated propionic acids which is diflicult to separate. The high price of B-iodopropionic acid prohibits the industrial production of fi-chloropropiomc acid therefrom. In order to convert hydracrylic nitrile into chloropropionic nitrile, expensive inorganic acid chlorides are neces sary. The preparation of ,B-chloropropiomc acid from hydracrylic nitrile by way of the sodium salt of hydracrylic acid and acrylic acid necessitates several inconvenient proccases.

We have now found that the esters of B- chloropro'pionic acid are obtained directly in a simple and inexpensive manner by way of ,H-chloropr'opionic acid by adding hydrogen chloride on to the readily accessible acrylic nitrile and saponifying and esterifying the resulting fi-chloropropionic nitrile by means of hydrochloric acid and the alcohol desired. The addition of hydrogen chloride on acrylic nitrile can be carried out by introducing gaseous hydrogen chloride into the nitrile or by mixing the nitrile with concentrated, from say 30 to per cent, aqueous hydrochloric acid and saturating with gaseous hydrogen chloride, whereby a simultaneous addition of hydrogen chloride and a saponification of the nitrile occurs. The esters separate from the aqueous h drochloric acid in most cases and can there ore readily be isolated. Any monoor poly-hydricalcohols, which term is. meant to include derivatives ofpolyhydric alcohols containing free hydroxyl groups, as for example ethylene chlorhydriii, ethylene lycol mono-methyl ether and the like, mayhydrogen chloride or before 'or after the saponification of the nitrile.

Thus esters of B-chloropropionic acid are obtained in good yields in one operation without isolating the acid itself.

e employed for the. esterification. The alcohol may be added to the reaction mixture before adding onthe.

1881, aerial Ito. 534,894, and in Germany Hay 7, 1980.

The following examples will further illustrate the nature of this invention, but theinvention is not restricted to these examples. The parts are by weight.

Example 1 I 100 parts of acrylic nitrile are treated at room temperature with gaseous hydro n chloride in a vessel provided with a re ux condenser until the specific gravity of the solution has risen from 6.78 to 1.144. 150 parts of concentrated hydrochloric acid are allowed to flow into the resulting crude B-chloropropionic nitrile, cooling being employed at the commencement on working on a large scale. After about 10 minutes the ammonium chloride formed by thesaponification commences to separate out. The whole is then heated to 100 C. for 1 hour while continually leading in gaseous hydrogen chloride and then 62 parts of methanol are added. After another 10 minutes the reaction mixture is cooled and filtered. The filtrate separates into two layers the upper layer consisting of B-chloropropionic methyl ester. The ammonium chloride filtered oil is dissolved in water in order to recover the ester adhering to the ammonium chloride. After drying with the aid of anhydrous sodium sulphate or of calcium chloride the'crude B- chloropropionic acid ester is practically pure. The yield amounts to 220 parts, i. e. 96 per cent of the theoretical yield.

The concentrated aqueous hydrochloric acid separated 011' contains the small amounts of ,B-chloropropionic acid and alcohol which have escaped the reaction. By employing this hydrochloric acid again, the total yield by carrying out the process becomes practically quantitative.

Ewample 2 100 parts of acrylic nitrile are converted into B-chloropropionic nitrile according to Example 1, 150 parts of concentrated hydrochloric acid and parts of ethanol are added and the whole is boiled under a reflux condenser for 2 hours while leading in gaseous hydrogen chloride. The whole is worked up as described in Example 1. The yield of B'- centrated chloropropionic ethyl ester amounts to about yiel . Ewample 3 100 parts of ac lic' nitrile are placed in a vessel capable of ing'closed and provided with a stirrer. The vessel is closed and the air is then displaced from the vessel by means of ous hydrogen chloride, and t e leading in of hydrogen chloride being continued at any suitable pressure and at room temperature until the increase in weight amounts to 69 arts. 150 parts'oi a 30 per cent ueous h diochloric acid and 202 arts of nzyl a cohol are then allowed to ow in. As soon first ta es lace has subsided, the whole is heated to oilin for about 2 hours while continually leading in gaseous hydro en chloride, it is then allowed to cool and wor ed up as described in Examples 1 and 2. The yield amounts to 366 parts, i. e. 98 per cent of the theoretical yield.

Example 4 100 parts of acrylic nitrile are converted into ,B-chloropropionic nitrile as described in Example 1 and the nitrile is then saponified.

Ewamqrle 5 100 parts of acrylic nitrile are converted into B-chlorop'ropionic nitrile as described in Example 1, whereupon the nitrile is refluxed for 2 hours together with 150 parts of conh drochloric acid and 160 parts of eth lene chl orhydrin. The reaction mixture is then worked up as described in Example 1, 300 parts ofthe fl-chloropropionic chlorethyl ester being obtained corresponding to from 92 to 94 per cent of the theoretical yield.

Example 6' drochloric acid. 155 parts of ethylene glycol mono-methyl ether are then added, whereupon the mixture is refiuxed for 1 hour while saturating it with gaseous hydrochloric acid. The reaction obtained corresponds to a yield of from 95 to 97 per cent of the theoretical yield.

What we claim is:- 1. The process forthe production of chloropropionic esters which comprises adding hydrochloric acid on acrylic mtrile, directly sapomfymg the resulting chloropro iomc mtrile and estenfymg the resultin c oroprop1 omc acid in the presence 0% hydrochloric acid.

2. The process for the production of chloroproplomc esters which comprises adding hydrochloric acid on acrylic nitrile in the presence of an alcohol, directly sa ni ing the resultmgchloropropionic nitri e an esterifymg the resulting chloropropionic acid with the alcohol resent by means of anhydrous hydrochloric acid.

3. The process for the production of chlo- 'ro ro' io as the s ontaneous evolution of heat which at h p p me esters which compnses addmg ydrochloric acid on acrylic nitrile actin on the result ng reaction mixture with h rochloric acid in the presence of water, addin an alcohol and acting on the mixture witE anhydrous hydrochloric acid.

4. The process for the production of chloroproplomc esters which hydrochloric acid on acrylic nitrile, acting on the resulting reaction mixture with h drochloric acid in the presence of water, ding an alcohol and acting on the reaction mixture at about its boiling point with anhydrous hvdrochloric acid.

In testimony whereof we have hereunto set our hands.

. HANS FIKENTSCHER.

BERNHARD JAOOBI.

comprises adding 

